History of Stealth Aircraft: Russian Science and American Engineering

From Skunk Works: A Personal Memoir of My Years at Lockheed (Ben Rich)…

The stealth story actually began in July 1975, about six months after I took over the Skunk Works. … The U.S. had only two defensive ground-to-air missile systems deployed to protect bases—the Patriot and the Hawk, both only so-so in comparison to the Soviet weapons. By contrast, the Russians deployed fifteen different missile systems to defend their cities and vital strategic interests. … Their early-warning radar systems, with 200-foot-long antennas, could pick up an intruding aircraft from hundreds of miles away. Those long-range systems couldn’t tell altitude or the type of airplane invading their airspace, but passed along the intruder to systems that could. Their SAM ground-to-air missile batteries were able to engage both low-flying attack fighters and cruise missiles at the same time. Their fighters were armed with warning radars and air-to-air missiles capable of distinguishing between low-flying aircraft and ground clutter with disarming effectiveness. The Soviet SAM-5, a defensive surface-to-air missile of tremendous thrust, could reach heights of 125,000 feet and could be tipped with small nuclear warheads. At that height, the Soviets didn’t worry about impacting the ground below with the heat or shock wave from a very small megaton atomic blast and estimated that upper stratospheric winds would carry the radiation fallout over Finland or Sweden. An atomic explosion by an air defense missile could bring down any high-flying enemy bomber within a vicinity of probably a hundred miles with its shock wave and explosive power.

we were subjected to a chilling analysis of the 1973 Yom Kippur War involving Israel, Syria, and Egypt. … Although the Israelis flew our latest and most advanced jet attack aircraft and their combat pilots were equal to our own, they suffered tremendous losses against an estimated arsenal of 30,000 Soviet-supplied missiles to the Arab forces. The Israelis lost 109 airplanes in 18 days, mostly to radar-guided ground-to-air missiles and antiaircraft batteries, manned by undertrained and often undisciplined Egyptian and Syrian personnel. What really rattled our Air Force planners was that the evasive maneuvering by Israeli pilots to avoid missiles—the same tactics used by our own pilots—proved to be a disaster. All the turning and twisting calculated to slow down an incoming missile made the Israeli aircraft vulnerable to conventional ground fire.

The truth is that an exceptional thirty-six-year-old Skunk Works mathematician and radar specialist named Denys Overholser decided to drop by my office one April afternoon and presented me with the Rosetta Stone breakthrough for stealth technology. The gift he handed to me over a cup of decaf instant coffee would make an attack airplane so difficult to detect that it would be invulnerable against the most advanced radar systems yet invented, and survivable even against the most heavily defended targets in the world. Denys had discovered this nugget deep inside a long, dense technical paper on radar written by one of Russia’s leading experts and published in Moscow nine years earlier. That paper was a sleeper in more ways than one: called “Method of Edge Waves in the Physical Theory of Diffraction,” it had only recently been translated by the Air Force Foreign Technology Division from the original Russian language. The author was Pyotr Ufimtsev, chief scientist at the Moscow Institute of Radio Engineering.

“Ben, this guy has shown us how to accurately calculate radar cross sections across the surface of the wing and at the edge of the wing and put together these two calculations for an accurate total.”

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